chore(deps-dev): Bump the vitest group with 2 updates

Bumps the vitest group with 2 updates: [@vitest/coverage-istanbul](https://github.com/vitest-dev/vitest/tree/HEAD/packages/coverage-istanbul) and [vitest](https://github.com/vitest-dev/vitest/tree/HEAD/packages/vitest).


Updates `@vitest/coverage-istanbul` from 4.0.13 to 4.0.15
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v4.0.15/packages/coverage-istanbul)

Updates `vitest` from 4.0.13 to 4.0.15
- [Release notes](https://github.com/vitest-dev/vitest/releases)
- [Commits](https://github.com/vitest-dev/vitest/commits/v4.0.15/packages/vitest)

---
updated-dependencies:
- dependency-name: "@vitest/coverage-istanbul"
  dependency-version: 4.0.15
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: vitest
- dependency-name: vitest
  dependency-version: 4.0.15
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: vitest
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -72,7 +72,7 @@
     "@nextcloud/typings": "^1.10.0",
     "@nextcloud/vite-config": "^2.5.2",
     "@types/node": "^24.10.1",
-    "@vitest/coverage-istanbul": "^4.0.13",
+    "@vitest/coverage-istanbul": "^4.0.15",
     "fast-xml-parser": "^5.3.2",
     "jsdom": "^27.2.0",
     "tslib": "^2.8.1",